21. the gulf of execution
represents the difficulty the
user has in translating a
psychological goal into a
physical action
22. for example, the goal learn more about
avocados is purely psychological
the user of a hypertext system on the WWW will
need to see the available links, recognize the
appropriate choice, and use the mouse to point
and click on that link
thus, in order to learn more about avocados, the
user needs to execute a set of physical steps
23. the gulf of evaluation
represents the user's
difficulty in evaluating
whether the response of the
computer system meets the
desired goal
24. in the previous example, the user would need to
perceive the system response, examine the
resulting node, and assess whether it presented
the proper information about avocados
26. KLM quantifies operations
such as…
K Press a key or button
P Point to a target on the
display
H Home hands on input device
D Draw a line segment
M Mentally prepare for an action
R (system response time)
29. goals are what the user wants to achieve and
can be broken down into subgoals
operators are actions performed in service of a
goal and can be perceptual,
cognitive or motor acts
methods are sequences of operators and
subgoal invocations accomplishing
a specific goal
selection rules represent the user’s knowledge
of which method should be applied
![[M2]
classical theories
cognitive modeling](https://image.slidesharecdn.com/m2lectureslides-141001092848-phpapp02/85/IFI7159-M2-1-320.jpg)
